/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.reactive.result.method.annotation;

import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.core.MethodParameter;
import org.springframework.core.ReactiveAdapterRegistry;
import org.springframework.http.HttpCookie;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.web.bind.annotation.CookieValue;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.ServerWebInputException;

/**
 * Resolve method arguments annotated with {@code @CookieValue}.
 *
 * <p>An {@code @CookieValue} is a named value that is resolved from a cookie.
 * It has a required flag and a default value to fall back on when the cookie
 * does not exist.
 *
 * @author Rossen Stoyanchev
 * @since 5.0
 */
public class CookieValueMethodArgumentResolver extends AbstractNamedValueSyncArgumentResolver {

    /**
     * @param factory a bean factory to use for resolving  ${...}
     * placeholder and #{...} SpEL expressions in default values;
     * or {@code null} if default values are not expected to contain expressions
     * @param registry for checking reactive type wrappers
     */
    public CookieValueMethodArgumentResolver(@Nullable ConfigurableBeanFactory factory,
            ReactiveAdapterRegistry registry) {

        super(factory, registry);
    }


    @Override
    public boolean supportsParameter(MethodParameter param) {
        return checkAnnotatedParamNoReactiveWrapper(param, CookieValue.class, (annot, type) -> true);
    }

    @Override
    protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) {
        CookieValue ann = parameter.getParameterAnnotation(CookieValue.class);
        Assert.state(ann != null, "No CookieValue annotation");
        return new CookieValueNamedValueInfo(ann);
    }

    @Override
    protected Object resolveNamedValue(String name, MethodParameter parameter, ServerWebExchange exchange) {
        HttpCookie cookie = exchange.getRequest().getCookies().getFirst(name);
        Class<?> paramType = parameter.getNestedParameterType();
        if (HttpCookie.class.isAssignableFrom(paramType)) {
            return cookie;
        }
        return (cookie != null ? cookie.getValue() : null);
    }

    @Override
    protected void handleMissingValue(String name, MethodParameter parameter) {
        String type = parameter.getNestedParameterType().getSimpleName();
        String reason = "Missing cookie '" + name + "' for method parameter of type " + type;
        throw new ServerWebInputException(reason, parameter);
    }


    private static class CookieValueNamedValueInfo extends NamedValueInfo {

        private CookieValueNamedValueInfo(CookieValue annotation) {
            super(annotation.name(), annotation.required(), annotation.defaultValue());
        }
    }

}
